Among the slaves at L'Abri there is wonderment at the appearance of Desiree's baby. Certainly, they would be able to recognize a mulatto, as mixed light-skinned blacks were termed during the time of Chopin's story. Probably, the slaves would assume that Master Armand's wife, whom they would know is of "obscure origin," has a rather clouded ancestry which could easily include miscegenation, which was not uncommon in the Deep South. Another reason that they may suspect Madame Armand's racial make-up is the fact that she was mysteriously found by Madame Valmonde. Perhaps, then, she was discarded by a white mother who had forbidden pleasures, or by a father who wished to hide his licentiousness from the mistress of the plantation.
At any rate, it is apparent that the slaves have recognized the baby as a non-white child. For, when Madame Valmonde visits Desiree, she exclaims, "This is not the baby!"
Madame Valmonde had never removed her eyes from the child. She lifted it and walked with it over to the window that was lightest. She scanned the baby narrowly, then looked as searchingly at Zandrine ["the yellow nurse woman"--a mulatto, herself] whose face was turned to gaze across the fields.
Clearly, Mme. Valmonde sees the likeness between her grandchild and Zandrine. And, later in the narrative as Desiree sits languidly in her room, no longer Armand's pet, one of the quadroon [one-fourth black] boys fans her,
She looked from her child to the boy who stood beside him, and back again; over and over. "Ah!" It was a cry that she could not help
Now, Desiree herself knows why there has been "an air of mystery among the blacks." They have recognized her baby as like the quadroon boys. The baby is apparently of mixed race.